[3+2] Coupling of Quinone Monoacetals with Vinyl Ethers Effected by Tetrabutylammonium Triflate: Regiocontrolled Synthesis of 2-Oxygenated Dihydrobenzofurans

The synthesis of 2-oxygenated dihydrobenzofurans involving the [3 + 2] coupling of quinone monoacetals with vinyl ethers has been realized by tetrabutylammonium triflate catalysis. The reaction involves a new activation method of the acetal moiety in quinone monoacetals under acid-free conditions affording the highly oxygenated dihydrobenzofurans. This new activation mode was achieved by using the triflate anion catalyst for stabilization of the highly reactive cationic intermediate.

Automated summary

The synthesis of 2-oxygenated dihydrobenzofurans via [3 + 2] coupling of quinone monoacetals with vinyl ethers has been achieved using tetrabutylammonium triflate catalysis. This new method involves activating the acetal moiety in quinone monoacetals under acid-free conditions to obtain highly oxygenated dihydrobenzofurans, with triflate anion catalyst stabilizing the cationic intermediate.